Making the safe decision (AKA "I hate AIRMET ZULU")

On Mon, 24 Oct 2005 01:37:41 +0000 (UTC), (Paul
Tomblin) wrote:

I'm just not sure when the conditions are
going to be conducive to bringing the plane home, and the club is NOT
going to be happy about that.

Yes, they would have been much happier had you become an icing accident.

Seriously, if the club is second guessing your decision, there's something
very wrong with the safety culture there.


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

In a previous article, Ron Rosenfeld said:
On Mon, 24 Oct 2005 01:37:41 +0000 (UTC), (Paul
Tomblin) wrote:
I'm just not sure when the conditions are
going to be conducive to bringing the plane home, and the club is NOT
going to be happy about that.

Yes, they would have been much happier had you become an icing accident.

Well, the guy who had it booked for Monday and Tuesday wrote to me that
he'd been thinking of cancelling anyway because of the weather, so I feel
better about that.

This morning I look at the airmets, and there are two of them for icing,
with a narrow little corridor between them straight between BAF and ROC.
Not sure if I trust that narrow corridor to stay open, though. How good
are the boundaries of airmets? Are you ever going to encounter the
conditions outside the boundaries, or are they pretty conservative about
them?

--
Paul Tomblin http://xcski.com/blogs/pt/
Programmer (n): One who makes the lies the salesman told come true.

"Paul Tomblin" wrote in message
...
How good
are the boundaries of airmets? Are you ever going to encounter the
conditions outside the boundaries, or are they pretty conservative about
them?

Icing is hardly ever as predictable as we'd like but my personal experience
is that I've found that the boundaries are usually broader than actual icing
conditions, but the accumulation rates can be both more and or less severe
than indicated in the airmet because it is also unpredictable and is highly
dependent on your speed and time spent in the conditions. I also fly around
the great lakes, and downwind from the lake is a great place to find ice
building faster than predicted and faster than you can get out of it.
Usually when the windward side is CAVU, the lake effect layer on the leeward
side isn't very thick, but you sure as hell don't want to be stuck in it
very long. If the windward side is IFR and tops into the teens or higher,
the lake effect moisture is just added to those conditions on the leeward
side, and you've probably lost all your "outs". Stay away... stay far away.

I've found that the ADDS forecast has been pretty accurate. If I can get
above a potential icing layer that isn't too thick, fly towards warmer
conditions and then do a slam dunk down through it into warmer and clear
conditions near my destination, I'll give it some serious consideration. If
I don't have at least 3 "outs", (altitude, distance, improving weather,
higher temps, between layers, ect.) I won't consider it.

This weekend in WI was a perfect case of airmets galore, but good planning
wouldn't have prevented flying due to ice. Overcast at 2700, clear above
3000.(4000 MSL) light to moderate rime ICIP airmet blanketing the entire
state. VFR both south and north of us, surface temps between 40 and 45F.
Freezing level 4000 MSL north sloping to 6000 MSL south. ADDS was
predicting a 80-90% chance of icing at 6000, nothing at 3000, and nothing at
9000. The "go" decision could be made because the clouds at 2700-3000 AGL
were below the freezing level and it was clear above, so the airmet didn't
have any weather that it applied to. Be careful when using ADDS that you
remember ceilings are AGL, icing predictions are MSL. So, we could have
taken off, climbed through the ceiling into clear air.

What if we come upon a layer at 6000 where ADDS said 80-90% chance of ice?

What are our outs?
1) Climb above it, ADDS predicted 0% at 9000, climb is always my first
choice. you can climb before you accumulate ice, you can always go down.

2) descend below it and continue, MEA is 3000 MSL

3) descend through it and land

4) turn around and fly back into clear weather

5) turn 90 degrees to the system and fly around it, this requires knowledge
of the area of coverage and conditions surrounding it, plus additional fuel.

I hate airmet zulu as well, it always throws the unknown at you. All we can
do is explore all our options, set minimal standards, do extra planning, and
be willing to stay on the ground. Fly safe.

Jim

: This weekend in WI was a perfect case of airmets galore, but good planning
: wouldn't have prevented flying due to ice. Overcast at 2700, clear above
: 3000.(4000 MSL) light to moderate rime ICIP airmet blanketing the entire
: state. VFR both south and north of us, surface temps between 40 and 45F.
: Freezing level 4000 MSL north sloping to 6000 MSL south. ADDS was
: predicting a 80-90% chance of icing at 6000, nothing at 3000, and nothing at
: 9000. The "go" decision could be made because the clouds at 2700-3000 AGL
: were below the freezing level and it was clear above, so the airmet didn't
: have any weather that it applied to. Be careful when using ADDS that you
: remember ceilings are AGL, icing predictions are MSL. So, we could have
: taken off, climbed through the ceiling into clear air.

: What if we come upon a layer at 6000 where ADDS said 80-90% chance of ice?

: What are our outs?
: 1) Climb above it, ADDS predicted 0% at 9000, climb is always my first
: choice. you can climb before you accumulate ice, you can always go down.

: 2) descend below it and continue, MEA is 3000 MSL

: 3) descend through it and land

: 4) turn around and fly back into clear weather

: 5) turn 90 degrees to the system and fly around it, this requires knowledge
: of the area of coverage and conditions surrounding it, plus additional fuel.

6) Stay VFR at 2500 AGL? If it's overcast at 2700, staying out of the iced-up soup
altogether seems like a good plan as well. I'd rather be at 1500 AGL in VMC than
slogging through the soup waiting for ice to start accumulating and have to choose an
"out"

-Cory


--

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

wrote:

: This weekend in WI was a perfect case of airmets galore, but good planning
: wouldn't have prevented flying due to ice. Overcast at 2700, clear above
: 3000.(4000 MSL) light to moderate rime ICIP airmet blanketing the entire
: state. VFR both south and north of us, surface temps between 40 and 45F.
: Freezing level 4000 MSL north sloping to 6000 MSL south. ADDS was
: predicting a 80-90% chance of icing at 6000, nothing at 3000, and nothing at
: 9000. The "go" decision could be made because the clouds at 2700-3000 AGL
: were below the freezing level and it was clear above, so the airmet didn't
: have any weather that it applied to. Be careful when using ADDS that you
: remember ceilings are AGL, icing predictions are MSL. So, we could have
: taken off, climbed through the ceiling into clear air.

: What if we come upon a layer at 6000 where ADDS said 80-90% chance of ice?

: What are our outs?
: 1) Climb above it, ADDS predicted 0% at 9000, climb is always my first
: choice. you can climb before you accumulate ice, you can always go down.

: 2) descend below it and continue, MEA is 3000 MSL

: 3) descend through it and land

: 4) turn around and fly back into clear weather

: 5) turn 90 degrees to the system and fly around it, this requires knowledge
: of the area of coverage and conditions surrounding it, plus additional fuel.

6) Stay VFR at 2500 AGL? If it's overcast at 2700, staying out of the iced-up soup
altogether seems like a good plan as well. I'd rather be at 1500 AGL in VMC than
slogging through the soup waiting for ice to start accumulating and have to choose an
"out"

Except 200' below the clouds doesn't meet the VFR minimums in most
classes of airspace.

Matt

Matt Whiting wrote:
: slogging through the soup waiting for ice to start accumulating and have to choose an
: "out"

: Except 200' below the clouds doesn't meet the VFR minimums in most
: classes of airspace.

So fly at 2200'. The east/west rules aren't required if below 5000 AGL IIRC.
If you want to call it MVFR, great. I'm just saying I'll take MVFR to icy soup in my
spamcan. Once you're IMC you're "committed" and things like altitude and heading
deviations take (possibly lots of) time, unless you declare an emergency.

-Cory

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

So fly at 2200'. The east/west rules aren't required if below 5000 AGL IIRC.

3000 AGL in the US.

Jose
--
Money: what you need when you run out of brains.
for Email, make the obvious change in the address.

wrote:

Matt Whiting wrote:
: slogging through the soup waiting for ice to start accumulating and have to choose an
: "out"

: Except 200' below the clouds doesn't meet the VFR minimums in most
: classes of airspace.

So fly at 2200'. The east/west rules aren't required if below 5000 AGL IIRC.
If you want to call it MVFR, great. I'm just saying I'll take MVFR to icy soup in my
spamcan. Once you're IMC you're "committed" and things like altitude and heading
deviations take (possibly lots of) time, unless you declare an emergency.

Yes, I'd call that MVFR. I believe the cutoff for east/west altitude
rules is 3000 AGL, but that wasn't my point. The point is that the
original suggestion was illegal in most airspace.

I'd rather fly IFR at a safe altitude and get around the ice, than scud
run in mountainous terrain just below the cloud bases and wonder when
the mountains and the bases will become one.

I flew in an area of icing potential just last weekend and had little
problem finding an ice-free altitude. I had to change altitude several
times to stay between layers, but in weather like that, there is very
little traffic below 10,000 feet, even in the northeast. I found new
altitudes to take less than 30 seconds toget, and it took that long only
because the controller volunteered to talk to a few other aircraft to
find the most promising altitude for me. I've found the controllers to
be extremely helpful on days like that. Just ask for their help BEFORE
you get in trouble, don't do something stupid and then drop the problem
in their lap.

Matt

On Mon, 24 Oct 2005 11:28:22 +0000 (UTC), (Paul
Tomblin) wrote:

In a previous article, Ron Rosenfeld said:
On Mon, 24 Oct 2005 01:37:41 +0000 (UTC), (Paul
Tomblin) wrote:
I'm just not sure when the conditions are
going to be conducive to bringing the plane home, and the club is NOT
going to be happy about that.

Yes, they would have been much happier had you become an icing accident.

Well, the guy who had it booked for Monday and Tuesday wrote to me that
he'd been thinking of cancelling anyway because of the weather, so I feel
better about that.

This morning I look at the airmets, and there are two of them for icing,
with a narrow little corridor between them straight between BAF and ROC.
Not sure if I trust that narrow corridor to stay open, though. How good
are the boundaries of airmets? Are you ever going to encounter the
conditions outside the boundaries, or are they pretty conservative about
them?

I have not looked in detail at weather in the NY area today. However,
given the general picture these past few days, I would not fly in a
non-deice'd a/c in the clouds higher than the freezing level. There's a
lot of moisture in these clouds.

An FIP map that I downloaded last night valid at 0900Z showed significant
icing probability along your route at 6,000', although it did look doable
at 3,000'.

I flew today from Eastport to Bangor and back in my non-deiced Mooney. But
I stayed at 3,000' and had no ice -- occasional light rain that sure would
have been ice had I been above the FL (about 4,000'). Here, with little
traffic, there were still scattered reports of icing.

One thing that's real important in flying, is to not weigh factors like "so
and so has the plane booked for whenever so I should try harder to get it
back to home base". That's just another form of "get-home-itis".


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

In a previous article, Ron Rosenfeld said:
An FIP map that I downloaded last night valid at 0900Z showed significant
icing probability along your route at 6,000', although it did look doable
at 3,000'.

The MEA between CTR and ALB is 6,000 though. I'm looking at the
possibility of going VFR to the Hudson Valley and then the Mohawk Valley.
But there are still those hills to the south of Rochester.

Thanks for you advice and everybody else's on this thread. I feel like
I've made the right decision, but it's easy to second guess yourself.

--
Paul Tomblin http://xcski.com/blogs/pt/
"Man in the tower, this is the man in the bird, I'm ready to go, so give me
the word." "Man in the bird, this is the man in the tower, you sound funny,
delay's an hour." - Rod Machado